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1995-09-10
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730 lines
GSH-PC - 1 - SHW-1.01
----------------------------------------------------------------------
GSH-PC SSTV - CONVERTER
=======================
Copyright (C) 1995 G.Szabados-Hann
All Rights reserved.
About this program
==================
GSH-PC is a program for sending and receiving SSTV (Slow-Scan
Television) pictures. This program is not a multi-mode decoder for
FAX/RTTY/PACTOR/etc., it was designed specifically for SSTV.
However, the program only requires a very simple interface circuit and
offers very good picture quality.
Features:
- Supports all commonly used modes (ROBOT, SCOTTIE, SC-2 and MARTIN),
- Load / save in BMP and TIFF image formats.
- Needs a very simple hardware interface, only two op-amps.
- Up to 16 M. colours by VESA-norm. compatibility.
- Supports the real-time (VD-720) frame-grabber
- Split window for RX/TX.
Hardware requirements
=====================
1) PC and graphics adapter
The program runs on MS-DOS PCs with at least 640 KB memory.
It needs an 1MB VGA graphics adapter supporting the 640x480 VESA-mode,
15, 16 or 24 bits per pixel (VESA modes 272, 273 or 274).
It is suggested using at least a 386DX processor machine with VLB-VGA
board. Colour resolution is, depending on the VESA-mode, 32K, 64K
or 16M colours per pixel. The best available resolution will be
selected automatically.
2) Interface
============
To convert the audio signal between receiver and PC, a very simple
interface circuit is used - see the proposed circuits in appendix-1
at the end of this manual. This kind of interface circuit is used
by several other RTTY and SSTV programs.
GSH-PC - 2 - SHW-1.01
----------------------------------------------------------------------
3) Video Digitiser
==================
Using the VD-720 digitiser board, you are able to freeze an image
from any video source (FBAS input). The image is loaded directly
into the TX-Window and can be transmitted immediately.
Ordering information:
VD-720C: (Typ-FG01)
PHYTEC Messtechnik GMBH
Robert-Koch Str. 39
D-55129 Mainz. Tel.: +49/(0)6131/95883-8
This is an optional facility, you can also operate GSHPC without the
digitiser board.
Installation of GSPHC
=====================
Copy the compressed file "GSHPCZIP.EXE" into the directory you want,
and start the program; for example: c:\sstv\ghspc. This file is a
self-extracting program, simply start the executable file. After
"unzipping", the following files are available:
GSHPC.EXE SSTV Converter-Program.
UNIVESA.EXE VESA-Emulation program (TSR-Prg.)
VESAMOD.EXE Lists the supported VESA modes of the VGA adapter.
VGATEST.EXE Test program for VGA adapter boards.
SSTV.BAT Batch file to start GSHPC, incl. callsign and name.
GSHPC_D.DOC Operator Manual for GSHPC (German).
GSHPC_E.DOC Operator Manual for GSHPC (English).
NORMS_D.DOC Description of SSTV modes (German).
NORMS_E.DOC Description of SSTV modes (English).
UNIVESA.DOC Manual for the VESA emulator (English).
Demo-Images
===========
BIGTXT.TXT ASCII Example for generating text files.
NORTXT.TXT ASCII Example for generating text files.
AUTHOR.BMP 24-Bit BMP format picture file.
FRAU.TIF 24-bit TIFF format picture file.
SHUTTLE.BMP 8-Bit Colour BMP picture file.
PAPAGEI.TIF 8-Bit Colour TIFF picture file.
SSTV.BMP Main Mask in 24-Bit BMP format.
GSH-PC - 3 - SHW-1.01
----------------------------------------------------------------------
Starting GSHPC
==============
Before first starting GSHPC on your PC, you should delete any
configuration file MODE_DEF.CFG. This may possibly be an old version
from another user and could contain directories that do not exist on
your PC.
Start the program by typing:
GSHPC DL1XXX <return> ; if only the callsign is used
GSHPC "DL1xxx op: Name" <return> ; if space exists for the text
note: do not use spaces in your callsign!
The callsign and name are optional, they will be placed at the top
of the transmitted image.
If you have problems:
---------------------
- Check the VGA-adapter, use the VESAMOD.EXE and VGATEST.EXE programs.
- Install UNIVESA.EXE if the VGA-adapter does not supports VESA.
- Remove/disable unused drivers e.g. EMM-386, CD-ROM, Soundblaster.
Operation:
=========
The program is controlled by function-keys and pull-down selection
lists. The main functions can be selected by pressing the first
(underlined) character of the function-name. If opened, the neigh-
bouring functions can be reached by means of the TAB or Curs <-/->
keys. After selecting the desired item (Pg-up/Pg-down), the selected
function is executed by pressing the RETURN key. Use the ESC key
to exit the function without making any changes.
+--------------------------------------------------------------------+
| Mode Martin M1 | DL4SAW SSTV Converter | Version: SHW 1.00 |
+-------+-------+-------+-------+-------+-------+------+------+------+
| Mode | Load | Save | Fill | Paint | Word | Tx ##| Hold | Rx ##|
+-------+-------+-------+-------+-------+-------+------+------+------+
| |
| |
+----------------------------------+---------------------------------+
| TX window PICTURE.TIF | RX window PIC_0001.BMP |
+----------------------------------+---------------------------------+
| | |
| | |
| | |
| | |
| | |
| | |
| | |
| | |
| | |
+------+------+------+------+------+------+------+------+------+-----+
| /osc/| conf.| F-run| VIS | Fsave| Tx<Rx| Tx>Rx| Zoom+| Scope|Exit |
| F1 ##| F2 ##| F3 ##| F4 ##| F5 ##| F6 | F7 | F8 | F9 ##| F10 |
+----------------------------------+---------------------------------+
GSH-PC - 4 - SHW-1.01
----------------------------------------------------------------------
MAIN FUNCTIONS
--------------
Mode: Selection of SSTV-mode (default = Martin-1).
===== The file "norms.doc" shows an overview of the used SSTV norms.
The so-called "quasi" modes are not implemented.
Load: Loads images in BMP, TIFF or TXT-format into the TX-window.
=====
Bitmap-format images must have the filename extension
"xx.BMP", TIFF-Format images "xx.TIF".
In the case of BMP-format images, only the 8-bit Colour-Map
and 24-bit RGB formats (without compression) are supported.
The image size is limited to 1000 x 800 pixels.
TIFF has a lot of versions, for that reason I had to limit
the implementation supporting only the mainly used formats.
GSHPC supports only the "INTEL" format with single planar-
configuration and without LZW compression. By loading the
images they are cropped into the TX-window, the x/y ratio
is not changed. As in BMP format, only 8-bit Colour and
24-Bit RGB formats are supported.
Text files in special GSHPC format (.txt) can also be loaded.
Both examples show how to compose these files.
You can use any text editor to create and change them.
Save: Store images from RX-window:
=====
1) Open the Save-Window and select a directory.
2) Select TIF or BMP format. If you want to store the
image using the current autosave number (PIC_xxxx.)
enter RETURN. Otherwise enter the desired filename.
Use ESC to exit this function without change.
The autosave number is incremented (if used) automatically
and stored together with the save path in the configuration
file.
GSH-PC - 5 - SHW-1.01
----------------------------------------------------------------------
Fill: Test cards: The following built-in test cards are available
=====
* Grey step scale.
* Colour bars.
* Test card for colour resolution.
* Test card with grey step and colour bars.
* Test card for horizontal resolution.
* Background. The R,G,B components can be adjusted
independently.
Paint: Opening this window, you can select a colour and draw in the
====== TX-window using the mouse. A standard mouse-driver should be
installed beforehand on the COM2 interface.
Word: Enter text into the TX-window (16 x 8 characters).
=====
1) Available functions in Edit-Mode:
* Cursor, Page-up, Page-down, Home, <-,-> Delete, End
* TAB Change to Colour adjustment Mode.
* Alt-C Delete text, the background is transparent.
* Alt-I Append callsign. If entered on invoking the program,
the text (up to the first space) will be copied.
* Ctrl-Return Copy the text into the TX-window.
2) Functions in Colour Adjustment Mode;
* Cursor-Keys: Set background and foreground colour compo-
nents.
* Page-up/Page-down: Toggle between background and foreground
colour adjustment.
* The characters can be displayed on a transparent
background. Firstly, one of the background colour
components should be set to zero. After pressing the cursor
down key, all component values are set to "_", signalling
that transparent background has been activated.
* TAB Change to Edit-Mode.
* CTRL-Return: Enter the text into the TX-window.
Operating modes
================
Tx: Transmitting images in the pre-selected SSTV mode
===
* Press the Tx-key once; the image will be sent only once, TX-LED is
yellow.
* Press the Tx-key again: Endless transmission, TX-LED is red.
GSH-PC - 6 - SHW-1.01
----------------------------------------------------------------------
* Halt transmission; press ESC key.
* Pressing any other key enters the "mono" mode. The TX-LED
changes to yellow. Transmission will be stopped after sending
the current image.
Hld: Standby (default state),
==== All functions are available.
Rx: Receives images in the pre-selected SSTV mode.
===
* Press the Rx-key once; continuous reception, RX-LED is green.
* Press the Rx-key again; Stop reception on reaching the bottom of
the image, the RX-LED is yellow.
Pressing any other key sends GSHPC back to standby-mode.
Exceptions: the following function keys are available during
reception.
Horizontal and vertical synchronisation
========================================
- F1 H-Res: Horizontal reset / Search mode.
---------------------------------------------------
After starting the receive function, the program is looking for
synchronisation impulses according to the pre-selected mode.
In the case of noisy signals, or receiving in incorrect mode/
speed, the F1-LED is yellow, signalling that reception cannot
be started. If you are in the correct mode, the image begins to
to be written automatically after detection of the
synchronisation impulse. Alternatively, you can force a search
for the correct mode by means of pressing the F1-key. During
the search procedure, the F1-led is set to red. After a certain
time, depending on the signal quality, it switches to the
correct mode and starts image reception. The F1-LED is then set
to green. Each time the image has been synchronised incorrect-
ly, you can re-synchronise the image by pressing the F1-key.
During resynchronisation, the F1-LED is set to yellow.
There are some limitations, because some SSTV-modes use
the same horizontal frequency. The program cannot distinguished
between:
* Martin-1 and Martin-3 (selects M-1)
* Scottie-1 and Scottie-3 (selects S-1)
* 32s S/W and 16s B/W (selects 32s)
* 30s SC-2 and 60s SC-2 (selects SC-2 60s)
* 12s S/W and 24s B/W (selects 24s B/W Robot)
The so-called "quasi-mode" (256-line mode with a low horizon-
tal resolution) leads to the selection of the corresponding
128-line mode (e.g. Martin-2 -> Martin-4).
GSH-PC - 7 - SHW-1.01
----------------------------------------------------------------------
- F2 V-Res: Vertical restart
--------------------------
Pressing the F2-key, the receive cursor (small green arrow)
jumps to the first line and horizontal resynchronisation
is forced.
The F2-LED shows the reason for the last vertical reset;
* LED-off; Idle-state / manual restart by pressing "F2".
* LED-green;
- An Erroneous VIS-Signal was received (parity error)
- This mode/speed is not supported.
- There is no VIS-code in the vertical synchronisation signal.
* LED-red;
New mode/speed has been selected, caused by the VIS signal.
* LED-yellow:
- A valid VIS-signal was received, the mode/speed is not
changed.
- The VIS mode selection was barred (F4) or GSHPC was
already in the correct mode/speed.
The F2-LED is switched off after the 10th line.
- F3 F-Run: Free-Run (See F-key description)
- F4 VIS: Change of mode/speed on VIS signal enabled/disabled.
- F9 Osc.: Display-mode of the Scope function:
- Analogue F9-LED: yellow
- spectrum analyser F9-LED: green (default)
- off F9-LED: off
FUNCTION KEYS
-------------
F1: PC-crystal calibration - available only in the HOLD-State!
======================
The variation in frequency between PC oscillators does not allow
one to receive pictures initially without some slant. For this
reason, you will have to calibrate the timing in the following
manner.
1) Receive an image containing vertical lines in Martin-1 mode.
2) Press F1, to start the calibration.
3) Set the red line parallel to a vertical line in the image.
4) Press Ctrl-Return to store the corrected value.
Use Ctrl-D to set the default values. Pressing ESC exits
the calibration routine without storing the new value.
If calibrated while in Martin-1, GSHPC computes the calibration
factors for all modes/speeds. This means that all other modes can
be received without slant. In case some small individual correcti-
on of another mode is necessary, this can be done by starting the
correction routine whilst in this mode. This correction is then
stored for this mode only, not affecting the other modes.
GSH-PC - 8 - SHW-1.01
----------------------------------------------------------------------
Note, that there exists the facility to correct "old" modes
(e.g. B/W mode) in Free-Run operation. Using the Curs-up, down <-,
-> keys, you are allowed to adjust the frequency on-line, whilst
receiving. This adjustment will be not stored and is valid up to
the next change of mode/speed. Also pressing the End key restores
the original values (see also F3).
F2: Configuration
=============
The required parameter field can be chosen by Curs-Up/Down.
Use "Curs <-/->" to select the correct parameters.
The following parameters can be adjusted.
1) Serial Interface.
Valid values: COM-1 to COM-8.
2) SSTV output signal via:
- Off
- PC-speaker
- TxD pin of the selected COM-interface.
- PC-speaker and TxD pin of the selected COM interface.
3) PTT-Control:
- Off.
- RTS Pin of the selected COM interface.
4) Grey step header at the top of the SSTV image;
- Off: Header is not present.
- On : Header is present (not in ROBOT mode).
5) Show directory for the Load and Save Functions.
- Off: Do not show load/save directory.
- On: Show load/save directory.
6) Fast-Save on/off.
- Off: Fast-Save (F5) is disabled.
- On: Fast-Save is enabled.
The fast save function can only be used after selecting
a save directory and image file type (TIF/BMP).
The F5-LED shows the overall readiness of the Fsave
function.
By pressing Ctrl-D you can restore the default parameter values.
The autosave number is reset to PIC_0001. Use ESC to exit the
menu without storing the selected parameters.
F3: F-Run Free-Run Mode on/off
===========================
The "new" SSTV modes like Martin mode, can only be received in
Free-Run mode. In this mode it is not possible to switch off
the F-Run function.
GSH-PC - 9 - SHW-1.01
----------------------------------------------------------------------
To enjoy the advantages of receiving images without synchronisa-
tion disturbance, new SSTV modes were developed. These new modes
combine the advantages of SSTV and FAX. The horizontal
synchronisation impulse allows the receiver to resynchronise the
image during image transfer. Normally, the picture is synchro-
nised only at the beginning of the transfer. The receiver starts
running, then is de-coupled from the synchronisation impulses. It
is absolutely necessary for the receiver and transmitter to have
precise clock signals in these modes.
Also, the "old" SSTV-modes (B/W and ROBOT) can be received Free-
Run; assuming that both pieces of equipment are running at
precisely the same frequency. Small differences can be corrected
"on-line" using the following keys:
- coarse shift to the left: "UP"
- coarse shift to the right: "DOWN"
- fine shift to the left: "<-"
- fine shift to the right: "->"
- Set default values: Home or End
These adjustments will not stored and they are valid up to the
next change of SSTV mode.
F4: Automatic change of mode/speed on VIS-Signal enable/disable
===========================================================
A lot of SSTV transmitters use the VIS-signal (Vertical Interval
Signal) to force the receiver into the correct mode/speed.
The VIS signal is 300 ms long and modulated by an 8-bit code
in addition to a start and stop bit. See further information in
"NORMS.DOC".
F5: FSave: Fast-Save Function.
=========================
The FSave function allows the storing of received images without
opening the save menu. The FSave function must be previously
enabled. See also F2-key description.
GSH-PC - 10 - SHW-1.01
----------------------------------------------------------------------
F6: TX<<RX Copies Rx-window to Tx-Window
=====================================
F7: TX>>RX Copies Tx-window to Rx-Window
=====================================
F8: Zoom Rx-Window
===============
This function allows magnification of the image in the RX-window.
Pressing any key restores the main window. The image in the
Tx-window will be deleted.
Shift-F8 Zoom Tx-Window
==============
Similar to F8, this magnifies the image in the Tx-window.
Pressing any key restores the main window. The image in the
Rx-window will be deleted.
Ctrl-F8: Show fast video input / freeze
==============================
This function is available only when the digitiser board VD-720
has been installed correctly.
* The first pressing of Ctrl-F8 shows the fast video signal bl/wh.
This is not a real-time facility, the scan rate depends upon
the speed of your PC (approx. 3 pic/s. using a 486DX-40).
* The second pressing of Ctrl-F8 causes the last video sequence to
be stored in true colour mode. The max. colour resolution is
16M colours.
F9: Scope: Shows the SSTV video signal in two different modes
==========================================================
Pressing F9 selects the display mode;
* LED is off; Function is not activated.
* LED is green; AF-spectrum.
* LED is yellow; oscilloscope.
Using the oscilloscope function, the receiver must be adjusted
so that the video signal remains between 1500 and 2300 Hz.
Approximately +/-100 Hz deviation is tolerated.
Note that displaying the video signal is an additional load
on the PC. If using a slow PC and/or receiving in 128 line mode
displayed full size, the PC can reach its speed limit.
In this case, the received image is disturbed.
F10: Exit; Exit the program, back to DOS.
=====================================
All 'pull down' windows need to be closed before pressing the
F10 key. The currently used configuration, e.g. mode/speed,
load and save directory and scope mode are stored in the
configuration file.
GSH-PC - 11 - SHW-1.01
----------------------------------------------------------------------
Limitations of this version:
============================
- I/O address of digitiser board (300) is not changeable.
Known errors:
- Pressing Ctrl-C and Ctrl-Break cause some disturbance to the main
window.
- Problems when loading or saving images from/to non ready drives.
Repeated pressing of keys, after receiving the error message, can
lead to program breakdown. Ready the drive and then press any
key. After a certain time it will work, have patience!
Do not try to store images on your CD-drive, it will not work!
It is not recommended to use drives A: and B: for storing images.
- Problems when using 32-bit (PCI) VGA-adapters. These boards
use a (for GSHPC) unusual video-RAM organisation (4-byte for one
pixel).
- Using ET4000 VGA adapters the UNIVESA driver should be preloaded.
Copyright and registration notes
================================
(c) Copyright 1995 G.Szabados-Hann DL4SAW. All rights reserved.
Am Zündhütle 7a 76228 Karlsruhe / Germany
Tel./Fax.: 0721 / 47-53-19
For non commercial purposes (such as amateur radio) you have the
right to use this software without further permission. You can
copy and share it, but you are not allowed to charge more money
for it than your cost for a disk and postage (approx. $4).
Any commercial use of this software needs the written permission
of the author. Also, the distribution by shareware dealers and
SSTV modem manufacturers is prohibited.
This software, although thoroughly tested, may contain some bugs.
The software is provided "as is", with no warranty expressed or
implied. You use this program at your own risk, the author is not
responsible for any damage resulting by the use of this software.
If you like this software, you can register it by simply sending
DM 50.- or equivalent to the above address. The benefits include:
- you obtain the latest version,
- you are informed of news and updates,
- you support the further development of the software.
All brand and product names appearing in this manual may be trade
marks of their respective companies.
GSH-PC Appendix - 1/1 SHW-1.01
------------------------------------------------------------------------
Improved quality comparator interface
=====================================
Jumper PC
Tx-Level 10K 10K o----> Speaker
+---------+--####-+--####------------------o
0.1uF | | | o-+
<----||--->R 10K === === |
Tx-Mic. | |4n7 |4n7 |
-+- -+- -+- 47uf 1N4148 | RS-232
|---||-----+---|<|---+ | 9.pin.
+ | | | SUB-D
100k +-------+ | |
+--####-------+ | | MC- | |
| | 47k R | 1458/2 | +--o (3) TxD
Rx 1uF 4k7 | +----\ | | | |
>---||---####--+--|- \ | 1K | +-+--\ +----o (4) DTR
Audio- | OP-1 >--+--####-------|- \
input +---|+ / | | OP-2 >--------o (6) DSR
| +----/ 50K R<----|+ /
4k7 R MC-1458/1 Offset | +-+--/ +--o (7) RTS
| R 47k | |
-+- | | | o (5) GND
+ | | 1N4148 | |
|---||--+-------+----|>|----+ |
Tx-PTT 47uF | |
<---------------\| 2k2 | |
npn |-----####--------|<|-------------------+ |
/| 1N4148 |
-+- |------+
Fig-1: Circuit diagram of the suggested interface
OP-1 acts as an amplifier, OP-2 as a limiter. The supply voltage is
delivered by the lines DTR (+) and RTS (-). The program
sets these outputs accordingly.
The RTS pin can be used, if programmed to do so, for PTT-control.
You have two methods of transmitting SSTV images using this modem.
- output via PC speaker,
- output via TxD pin of the serial interface.
in both cases the jumper and the program parameter "Transmitting"
must be adjusted correctly (see this manual, F-2 key).
You can also use an alternative simple interface. It is only important
to keep the square-wave signal as symmetrical as possible.
Unfortunately, most op-amps, like the 741 have a big offset error. For
this reason, an additional offset adjustment is necessary. Minimise the
offset error when receiving a strong single carrier signal (e.g.
calibrator signal of your receiver). Enter the scope function (F9) and
monitor the video signal. Adjust the 50K offset trimmer for minimum
noise ripple.
GSH-PC Appendix - 1/2 SHW-1.01
------------------------------------------------------------------------
Another possibility is shown in fig-2. Using the CMOS op-amps CA-3240
no offset adjustment is necessary. Two diodes are added to protect
the input circuit against high voltage.
Jumper PC
Tx-Level 10K 10K o----> Speaker
+---------+--####-+--####------------------o
0.1uF | | | o-+
<----||--->R 10K === === |
Tx-Mic. | |4n7 |4n7 |
-+- -+- -+- 47uf 1N4148 | RS-232
2x1N4148 |---||---+---|<|---+ | 9.pin.
+-|<|-| 22K 1M + | | | SUB-D
| |-####-+--####-------+ | | |
+-|>|-| | | | CA- | |
| 22K | CA-3240/1 | | 3240/2 | +--o (3) TxD
| | +----\ | | |
| +--|- \ | 1K +-+--\ +----o (4) DTR
| 1uF (bipolar) | OP-1 >--+--####---|- \
+------||-------+--|+ / | OP-2 >--------o (6) DSR
| | +----/ |--####---|+ /
R 1K R 22K 1K +-+--/ +--o (7) RTS
Rx | | | |
>--+ -+- | | o (5) GND
+ | 1N4148 | |
|---||---+----|>|----+ |
Tx-PTT 47uF | |
<---------------\| 2k2 | |
npn |-----####--------|<|-------------------+ |
/| 1N4148 |
-+- |------+
Fig-2: Circuit diagram of the modified interface
Also a simple OP interface (Hamcomm) can be used. In this case the
741 should be replaced by the pin-compatible CMOS version CA3140.
In some cases it is necessary to change RTS and DTR, please compare
the circuit diagram of your modem with the above circuit.
Also the additional connection from TxD to the low pass filter, can
be necessary, if your interface does not support sending via the
TxD line.